Truss fabricating machine



July 4, 1967 J. c JUREIT ETAL TRUSS FABRICATING MACHINE 5 Sheets-Sheet 1 Filed July 13, 1965 INVENTORS JOHN C. JURElT BY THEODORE J. BOWMAN in-Alambiw ATTORNEYS.

July 4, 1967 J. c. JUREIT ETAL.

TRUSS'FABRICATING MACHINE 3 Sheets-Sheet 3 Filed July 15, 1965 INVENT ORS JOHN c. JUREIT y THEODORE J. BOWMAN m wk WZZZn ivumkl ATTORNEY-S.

United States Patent Filed July 13, 1965, Ser. No. 471,516 8 Claims. (Cl. 227-152) ABSTRACT OF THE DISCLOSURE A machine for fabricating bowstring trusses through the use of toothed connectors and toothed spacer-connectors comprising a pair of toothed plates connected by flanged webs. The apparatus utilizing a series of press means for embedding the teeth of the connectors and spacer-connectors in the chords of the truss after the chords have been positioned and clamped by locating and spacing means associated with the presses.

The present invention relates to a bowstring truss press and more particularly to such a press which is capable of utilizing spacer-connectors in forming the truss.

In mobile homes and other like framing installations, builders sometimes use a ceiling supporting structure commonly called a bowstring truss. This trussconsists of two elongated structural wood elements referred to as the upper and lower chords which are joined at their ends and are spaced midway of their ends by one or more transverse elements in the nature of spacing webs or struts. The chords are unitary pieces of wood several feet in length with the lower chord being substantially straight or having only a slight camber and the upper chord being bent or arched between its ends so that its center point midway between its ends is spaced several inches from the lower chord. The upper chord is prestressed into the arcuate or bent position and this curved shape is maintained by the previously mentioned intermediate Webs.

In the fabrication of the foregoing types of bowstring presses economy is an extremely important factor. To this end spacer-connector members, such as disclosed in copending application Ser. No. 396,823, filed Sept.16, 1964, now Patent No. 3,298,151, issued Jan. 17, 1967, have been devised for performing the dual function of spacing the chords to a desired configuration and also connecting them. These spacer-connectors will maintain the proper curvature of a bowstring truss, provide adequate strength thereto, maintain the sides of the truss parallel, in addition to providing other desirable characteristics set forth in detail in the above mentioned copending application. However, in the past, the above type of bowstring trusses were fabricated by hand with the attendant relatively high labor cost and the attendant lack of uniformity which is characteristic of hand operation.

It is accordingly one object of the present invention to provide a bowstring truss press which permits bowstring trusses to be fabricated by machine and thus further reduce their cost.

Another object of the present invention is to provide a bowstring truss press which is capable of producing bowstring trusses having an extremely high degree of uniformity.

A further object of the present invention is to provide a bowstring truss press which is capable of utilizing spacer-connector members in an extremely simple and expedient manner to thereby further increase the economy of fabrication.

Still another object of the present invention is to provide a bowstring truss press which is capable of automatically compensating for variationsin dimension of the chords utilized therein.

Yet another object of the present invention is to provide a bowstring truss press consisting of uniquely integrated, extremely simple and inexpensive components capable of providing long efiicient usage as well as a high degree of uniformity of the fabricated bowstring trusses produced thereby. Other objects and attendant advantages of the present invention will readily be perceived hereafter.

The bowstring truss press of the present invention includes a base on which are mounted a plurality of sub- .stantially aligned press heads. The press heads include clamping plate structure thereon for receiving and positioning a plurality of connector plates and a plurality of spacer-connectors in addition to orienting a pair of chords relative to each other. The press heads thereafter press the various connecting members into the chords to cause the latter to retain the desired configuration of the truss. The press heads include an unique spacer-locator arrangement for positioning the spacer-connectors as well as permitting them to shift, as is required during the clamping of the chords, to compensate for variations in thickness of the chords to thereby cause the spacer-connectors to provide connections of maximum strength. In addition the spacer-locators maintain the truss elements in their proper relationship until after fabrication has been completed to thereby insure the squareness and uniformity of the bowstring trusses made by the machine. The present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein FIGURE 1 is a plan view of the improved bowstring truss press of the present invention;

FIGURE 2 is a front elevational view of the bowstring truss press of FIGURE 1;

FIGURE 3 is a plan view of the bowstring truss produced by the press of FIGURES 1 and 2;

FIGURE 4 is a fragmentary view showing a portion of the end press head and taken substantially along line 4-4 of FIGURE 2;

FIGURE 5 is a fragmentary view of an intermediate press head and is taken substantially along line 5-5 of FIGURE 2;

FIGURE 6 is a view partially in cross section taken substantially along line 6-6 of FIGURE S and showing an intermediate press head and related structure in side elevation;

FIGURE 7 is a view taken substantially along line 7-7 of FIGURE 5 and showing the relationship between the upper and lower chords and the spacer-locator therebetween for insuring proper positioning of the chords during the process of truss fabrication;

FIGURE 8 is a view taken substantially along line 8-8 of FIGURE 4 and showing the relationship of the end press head, the connector members and one of the chords relative to each other during the process of fabrication;

FIGURE 9 is a view taken substantially along line 9-9 of FIGURE 8 and showing a detail of the upper portion of the press head;

FIGURE 10 is a cross sectional view taken substantially along line 10-10 of FIGURE 6; and

FIGURE 11 is a perspective view of a spacer-connector used in the fabrication of the bowstring truss.

The bowstring truss 10 which is formed by the press of the present invention is shown in FIGURE 3 and also forms the subject matter of copending application Ser. No. 396,823, filed Sept. 16, 1964, now Patent No. 3,298,-

151, issued Jan. 17, 1967. It is believed that a description of this truss is desirable at this point to facilitate the understanding of the press of the present invention. The bowstring truss 10 includes an upper chord 11 and a lower chord 12 joined at their ends onvboth sides by flat connector plates 13 which are flat rectangular strips of galvanized sheet metal having integral teeth punched therefrom. The connector plates may be of the form disclosed in United States Patent No. 2,877,520 or the form disclosed in copending application Ser. No. 293,949, filed July 10, 1963.

'Upper chord 11 is an integral elongated piece of lumber several feet in length and is provided with a substantial curvature at the center so as to define a spacing of several inches between it and lower chod 12. Lower chord '12 will ordinarily have a slight camber but this is small relative to the curvature of upper chord 11 and for the sake of clarity lower chord 12 is illustrated in the drawings as substantially straight.

Joining the upper chord 11 to lower chord 12 at spaced locations along the length of the chords are a plurality of intermediate spacer-connectors 14 and 15. The details of spacer-connector 15 are shown in FIGURE 11 and the other connectors 14 are of similar construction, the only difference being the length of the central web or channel of the connectors.

As can be seen from FIGURE 11, each connector 15 comprises an elongated central channel 16 having a substantially U-shaped cross section to define a pair of spaced flanges 17 with the connector terminating at each end at the flat rectangular plates 18. Punched out from the plates 18 so as to extend substantially perpendicularly thereto are a plurality of slender, nail-like elongated teeth 19 adapted to be driven into chords 11 and 12, as shown in FIGURE 3. 'It is deemed that the foregoing description of spacer-connectors 15 is sufficient to facilitate the ensuing description of the press 20.

The overall general orientation of the bowstring truss press 20 is shown in FIGURES 1 and 2. Press 20 includes an elongated base 21 which is essentially a table top mounted on spaced legs 22 and 23 which are reinforced by brace members 24 and 25, respectively, extending between said legs and said base 21. A plurality of press heads 1, 2, 3, 4, and 6 are mounted .in spaced relationship longitudinally of base 21. Press heads 1 and 6 are designated as end press heads and press heads 2, 3, 4 and 5 are designated as intermediate press heads because they are located between end press heads '1 and 6.

All of the press heads 1 through 6 have certain basic structure which is identical and this structure will now be described in conjunction with FIGURES 5 and 6 showing press head 2. Press head -2 includes a channeldike C frame 26 having a pair of spaced parallel lower portions 27 joined by web 28 (FIGS. 6 and 10). Portions 27 are located underneath base 21 and suitably secured thereto by connections which are not shown. Vertical portions 29 extend upwardly from and are integral with lower portions 27 and portions 29 merge into upwardly horizontally extending portions 30-. Vertical portions 29 are joined by Web 31 and upper portions 30 are joined by web 32. All of the foregoing joining is effected by suitable welding or the like. It is to be noted that the lower portion of the channel-like C frame consisting of portions 27 is mounted in a suitable cutout 33 in base 21 (FIGS. 1 and 2).

Press head 2 and all of the other press heads include an hydraulic motor 34 having a lower threaded portion 35 which is received in mating threaded engagement within tapped aperture 36 in web 32. Motor 34 includes a piston housing 37 and a piston shaft 38 extending therefrom for mounting a connector engaging head 39 at its lower end by means of set screw 40. Connector engaging head 39 fits on reduced end portion 41 of piston shaft 38. Head 39 is movable between the solid and dotted line positions of FIGURE 6. The movement from the solid line to the dotted line position is effected by admitting pressurized 4 hydraulic fluid into cylinder 37 through conduit 42. The piston 43 carried by shaft 38 moves downwardly against the bias of spring 44 when the pressurized hydraulic fluid is admitted to housing 37. If desired, an hydraulic line, not shown, may be used to admit pressurized hydraulic fluid to housing 37 below piston 43 to thereby rnove piston 43 upwardly as required, this structure being a substitute for spring 44. It is to be noted that piston shaft 38 moves between its solid and dotted line positions with a perfectly rectilinear motion and without rotating about its axis by virtue of a keyed connection between shaft 38 and web 31 consisting of a collar 45 secured to shaft 38- by screw 46 and having pin 47 extending therefrom the end of which rides in groove 48 in web 31. All of the press heads 1 through 6 contain structure which is identical to the structure described up to this point, except that connector engaging head 74 of presses 1 and 6 differ somewhat from heads 39, as will become apparent hereafter.

Intermediate press heads 2, 3, 4 and 5 differ in construction from end press heads 1 and 6 and the following portion of the description will relate to such intermediate press heads. In this respect each intermediate press head includes truss clamping plate 49 which is mounted on web 28 of the C frame. Each truss clamping plate 49 includes a base plate 50 having a pair of spaced elongated slots 51 (FIG. 5) therein for receiving screws 52 which serve to connect plates 50 to web 28. The elongated slots 51 are countersunk so that the heads of screws 52 lie below the upper surface of plate 50. It can readily be seen that after loosening screws 52, plate 50' may be moved toward and away from vertical web 31 with a rectilinear motion to thereby adjust the position of locator plate 53 which is secured to the end of plate 50, as by welding, and extends substantially perpendicularly therefrom in a Vertical direction proximate web 31. At this point it is to be noted that the various locator plates 53 of the truss clamping plates 49 are placed in the desired alignment by the use ofscrews 52, as described above, so that the lower chord 12 of bowstring truss 10 when laid in the position shown in FIGURE 1 will have its outer edge 54 abutting all of the plates 53 to thereby follow the configuration dictated thereby, whether straight or with a slight camber.

Each of the clamping plates 49 associated with intermediate press heads 2, 3, 4 and 5 carries an air clamp cylinder 55 which is secured to plate 50 by bracket 56 having screws 57 extending therethrough into plate 50. Each air clamp cylinder 55 includes a housing with a piston therein connected to piston shaft 58 mounting a clamping head 59 at the outer end thereof. A compressed air conduit 60 is in communication with cylinder 55 for conducting compressed air thereto. A spring (not shown) is provided within each air clamp cylinder 55 for biasing clamping head 59 toward conduit 60 so that when the cylinder 55 is not subjected to compressed air, head 59 will be pulled downwardly in FIGURE 5 or to the left in FIGURE 6.

At this point a brief description will be made of the structure of end press heads 1 and 6. Each of these press heads include a clamping plate which is very similar to clamping plate 49 described above with respect to FIG- URES 5 and 6 and is fastened to bottom web 28 in the same manner. Therefore for the sake of brevity the description relating to this structure will not be repeated. Clamping plate 60' of press head 1 however includes a locator plate 61 which is similar in both structure and function to locator plate 53 of FIGURE 5. However, an angle bracket 62 has an apertured leg 63 through which screws 64 extend for fastening bracket 62 to locator plate 61. The other leg 65 of bracket 62 serves as an end guide for positively locating the ends of upper and lower chords 11 and 12, as shown in FIGURE 4, locator plate 61 serving to locate the edge 54 of chord 12. Aside from the above described variation in the locator plate, all of the remainder of the structure of clamping plate 60' is identical to the heretofore described structure of intermediate clamping plate 49 shown in FIGURES 5 and 6.

Clamping plate 66 of press head 6 is substantially similar to clamping plate 60 of press head 1 except that bracket 62 is omitted because there is no need to locate the right ends of chords 11 and 12.

Each of the clamping plates 49 of intermediate press heads 2, 3, 4 and 5 includes acombined spacer-locator 67 which is utilized for spacing the chords 11 and 12 during the fabrication of the bowstring truss and also for positioning said spacer-connectors 14 and 15. Each of the spacer-locators 67 consists of a vertical plate 68 and a horizontal plate 69 secured perpendicularly thereto with said horizontal plate 69 lying on plate 50. A pair of slots 70 and 71 are located at opposite ends of horizontal plate 69 and receive the shanks of screws 72 which thread into plate 50 (FIG. 7). Screws 72 are sufliciently loose to permit spacer-locator 67 to float back and forth as required relative to web 31, with a perfectly rectilinear motion. It will be appreciated from FIGURES 1 and 3 that vertical portions 68 of spacer-locators 67 associated with press heads 2 and 5 are shorter than those associated with press heads 3 and 4 because of the difference in length of the webs of the spacer-connectors.

In order to fabricate a bowstring truss 10 with the bowstring truss press 20 of the present invention, the following steps are performed. Firstly, a flat connector plate 13 is laid on the base of clamping plate 60' as shown in FIG- URE 8 with the slender, elongated, tooth-like members pointing upwardly and the plate portions lying horizontally, connector plate 13 being located in proper position by lugs 73 which are essentially set screws having a portion projecting upwardly beyond the upper surface of clamping plate 60' (see FIG. 8). The same procedure is followed at press head 6 which has similar structure (not shown). Thereafter a connector plate 13 is secured to the underside of head 74 having magnets 75 embedded therein and suitably insulated from head 74 by plastic jackets 76. The magnets 75 hold connector plate 13 in the position shown in FIGURE 8 and suitable locator pins may be provided for positively positioning plate 13 in its desired location. Identical structure is supplied at press head 6.

After connector plates 13 have been positioned as described above at press heads 1 and 6, a shorter spacerconnector is positioned at press head 2 and a longer spacer-connector 14 is positioned at press head 4. Both of these are positioned in the manner shown in FIG- URES 5 and 7. More specifically, spacer-connector 15 is laid flat with its slender, elongated, tooth-like projections 19 extending upwardly. From FIGURE 5 it can be seen that the central channel-like portion 16 is positioned with one of the side flanges 17 in abutting relationship to vertical plate 68, the end plates 18 lying at opposite ends of vertical plate 68. It is to be noted that an upwardly projecting locating screw 74 extends upwardly from plate 50 and engages the side flange 17 which is opposite to the one engaged by vertical plate 68. The same manipulations are performed at station number 4 with a connector 14. Thus, at this time there are connector plates 13 located at both the upper and lower positions at press heads 1 and 6 and spacer-connectors 15 and 14 are located at the lower positions at press heads 2 and 4, respectively.

At this time chords 12 and 11 are placed in the machine. More specifically, lower chord 12 is positioned with the surface 54 thereof in contiguous relationship to locator plates 53 of press heads 2, 3, 4 and 5 and the left end of lower chord 12 is moved into abutting relationship with leg 65 of angle 62. It will readily be seen therefore that lower chord 12 now rests on the lower connector plates 13 at press heads 1 and 6 and on the lower spacerconnectors 14 and 15 at press heads 2 and 4. Further more, as can be seen from FIGURES 5, 6 and 7 and as can be visualized from FIGURE 1, lower chord 12 is positioned between the locator plate 53 and one end of vertical plate 68 of spacer-locator 67 at each of press heads 2, 3, 4 and 5. Thereafter upper chord '11 is placed into the machine with the left end thereof abutting leg 65 of angle 62, as shown in FIGURE 4, and its intermediate portions lying between the ends of plates 68 and clamping heads 59, as can readily be visualized from FIGURE 1.

After all of the foregoing positioning has been effected the bowstring truss 10 is deflected into its final configuration by air clamp cylinders 55. More specifically, a source of compressed air 77' is provided leading to conduit 77 (FIG. 2) which in turn leads to conduit 78 coupled to valve 79 which, in turn is coupled to conduit 80 which is in communication with conduit 81. Branch conduits 60 lead from conduit 81 to air clamp cylinders 55 and conduit 60 leads to the air clamp cylinder from conduit 80 at press head 5. Thus, whenever valve 79 is actuated the source of compressed air 77 will be placed in communication with air clamp cylinders 55 to thereby cause clamping heads 59 to be driven toward locator plates 53 at stations 2, 3, 4 and 5 and to be driven toward locator plates 61 at press heads 1 and '6.

It can therefore be seen that surface 54 of lower chord 12 will be driven against the vertical locator plates 53 and 61, and by virtue of the floating connection of spacerlocators 67, vertical plates 68 will be driven against surface 82 of lower chord 12. In addition surface 83 of upper chord 11 will be forced against the opposite end of vertical plates 68 as clamping heads 59 press against surface 84 of upper chord 11, this action occurring at all of the press heads 2, 3, 4 and 5. At press head 1, however, it is surfaces 82 and 83 of lower and upper chords 12 and 11, respectively, which are forced into engagement as shown in FIGURE 4. The same is true at press head 6.

Because of the above described action at press heads 2, 3, 4 and 5, it can be seen that the central channel portions of spacer-connectors 14 and 15 will have their opposite ends in perfect abutting relationship with surfaces 82 and 83 of the chords 12 and 11, and therefore be capable of providing a good reinforcing joint therewith; As noted above, the foregoing is obtainable by virtue of the floating connection of spacer-locators 67 on plates 50 of clamp plates 49. The floating connections of spacerlocators 67 insure a self-centering action of the spacerconnectors 14 and 15 having their central channel portions the same length as the plates 68 which adjoin them. Spacer-connectors 14 and 15 thus move with plates 68. In other words, the spacer-connectors 14 and 15 are properly positioned between the chords because the surfaces 82 and 83 are placed into abutting engagement with the ends of the central channels, such as' 16, to thereby insure a good tight fit, notwithstanding the variations in thickness of chords 11 and 12.

After the foregoing has been effected, that is after the chords 11 and 12 have been clamped, spacer-connectors 14 and 15 are placed on the top of chords 11 and 12 at press heads 3 and 5. In this respect it is merely necessary to insert the central web portion such as 16 of the spacerlocators so that the ends of said central portion are in firm engagement with surfaces 82 and 83 of lower and upper chords 12 and 11, respectively. It can readily be seen that the central web portions at press heads 3 and 5 may be moved longitudinally of chords 11 and 12 until such times as a good tight fit is obtained and at this time the spacer-connectors 14 and 15 will lie underneath heads 39 of press heads 3 and 5.

At this point, all that is necessary, after the spacer-connectors 14 and 15 and connector plates 13 have been located, is to cause all of the press heads 1 through '6 to securely fasten chords 11 and 12 relative to each other. To this end a source of hydraulic fluid 85 is provided. Associated with this source of hydraulic fluid is a valve 86 and a conduit 87 leading from that source to conduit 88 which is in turn in communication with conduits 42 leading to hydraulic motors 34. When valve 86 is opened,

high pressure hydraulic fluid willl communicate with cylinders 37 above pistons 43 and thus drive heads 39 and 74 of the various press heads 1 through 6 downwardly with a sufficient force to cause all of the spacer-connectors and all of the connectors plates to be driven into locking engagement with the clamped chords 11 and 12. It is to be especially noted at this time that the spacerlocator plates 67 at press heads 2, 3, 4 and 5 guide chords 11 and 12 downwardly during the pressing operation, and, thus, in addition to the other functions enumerated above, the spacer-locator plates 67 serve the additional function of causing the squareness of theresulting truss to be maintained during the fastening operation. After the fastening has been completed by the use of motors 34, valve 86 is closed to relieve the high hydraulic pressure and the pressurized fluid within motors 34 is permitted to bleed back to a source of low pressure hydraulic fluid not shown under the expansion ofsprings 44.

At this time all that remains is the act of removing the completed bowstring truss from base 21 of press and to facilitate this operation a plurality of ejectors 89 are located in base 21. These ejectors consist essentially of piston and cylinder arrangements with the cylinders fixedly fastened to base 21 and the pistons movable in a vertical direction to engage the undersurfaces of chords 11 and 12. Thus when valve 90 (FIG. 2) is opened, communication is established between compressed air source 77 and ejector motors 89 through conduits 77 and 91 to thereby cause the pistons within ejectors 89 to move upwardly and pop the completed truss off of base 21 so that it may readily be removed therefrom prior to the initiation of a subsequent truss fabricating operation which is identical to that described above.

It can thus be seen that the improved bowstring truss press forming the subject matter of the present invention is manifestly capable of achieving the above enumerated objects.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of the equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A machine for fabricating a bowstring truss consisting of a first chord and a second chord bowed relative to said first chord with said first and second chords secured to each other by connector means and combined spacer-connector means having a spacer portion and connector portions comprising a base, a plurality of press means placed in a predetermined orientation on said base including intermediate press means and end press means on opposite sides of said intermediate press means, locator means for positioning said first chord on said base relative to said plurality of press means, combined spacerlocator means located proximate said intermediate press means for spacing said second chord relative to said first chord and for locating said combined spacer-connector means relative to said first and second chords, clamping means for deflecting said second chord relative to said first chord as limited by said combined spacer-locator means and for clamping said second chord relative to said first chord with said combined spacer-locator means therebetween, and control means for causing said intermediate press means to press the connector portions of said combined spacer-connector means into said first and second chords after said second chord has been deflected and for causing said end press means to press said connector means into the end portions of said first and second chords to thereby effect the securing of said first and second chords to each other.

2. A machine for fabricating a bowstring truss as set forth in claim 1 including means for ejecting said howstring truss from the position on said base in which it was fabricated.

3. A machine for fabricating a bowstring truss as set forth in claim 1 wherein said combined spacer-locator means comprise plate members extending substantially perpendicularly from said base.

4. A machine for fabricating a bowstring truss as set forth in claim 3 including means for permitting said plate members on said base to float in a direction substantially perpendicularly to said chords and therefore be selfadjusting.

5. A machine for fabricating a bowstring truss as set forth in claim 4 including means for ejecting said howstring truss from the position on said base in which it was fabricated.

6. A machine for fabricating a bowstring truss comprising a first chord and a unitary bowed second chord engaging said first chord at its ends and secured thereto by toothed connector means at such ends and by spacerconnector means intermediate said ends, said spacer-connector means comprising toothed metal plates connected by integral flanged webs; comprising a plurality of press means disposed in a predetermined orientation and including intermediate press means and end press means on opposite sides of said intermediate press means, locator means for locating said first chord relative to said press means, spacer means for temporarily spacing said second chord relative to said first chord, clamping means for deflecting said unitary second chord into its bowed condition with its ends in engagement with said first chord and otherwise spaced therefrom as limited :by said spacer means temporarily disposed between said first and second chords, and means for causing said press means to embed the teeth of said toothed connector means and spacerconnector means in said chords to fasten said chords together with the flanges of said spacer-connectors spacing said chords after said spacer means are removed.

7. A machine for fabricating a bowstring truss consisting of first and second chords secured to each other by connector means and combined spacer-connector means having a spacer portion and connector portions comprising a base, a plurality of press means located in a predetermined orientation on said base including intermediate press means and end press means, locator means for positioning said first chord on said base relative to said plurality of press means, spacer means for spacing said second chord from said first chord, means for locating said spacer-connectors on said intermediate press means relative to said first and second chords, means for locating said connector means in said end press means, clamping means for clamping said first and second chords relative to each other and causing said chords to assume the configuration of a completed bowstring truss, means for causing said intermediate press means to drive the connector portions of said spacer-connector means into said first and second chords and for causing said end press means to drive said connector means into said first and second chords, said spacer means and said means for locating said spacer-connector means comprising plates extending substantially vertically from said base, said plates being positioned between said locator means and said clamping means, and means mounting said vertical plates for floating movement in a direction transverse to said chords to thereby effect firm clamping engagement of said first chord between said locator means and said vertical plate and effect firm clamping engagement of said second chord between said vertical plate and said clamping means irrespective of variations in thickness of said first and second chords.

8. A machine for fabricating a bowstring truss as set forth in claim 7 wherein said vertical plates include first 9 10 portions for locating said spacer-connectors relative to References Cited said intermediate press heads and second portions for UNITED STATES PATENTS guiding movement of said first and second chords in a. vertical direction during the driving of said connector ,por- 3,100,301 9 la k tions of said spacer-connector means and said connector 5 3,255,943 6/1966 Sanford 227152 means into said first and second chords by said press means. GRANVILLE Y. CUSTER, JR., Primary Examiner. 

1. A MACHINE FOR FABRICATING A BOWSTRING TRUSS CONSISTING OF A FIRST CHORD AND A SECOND CHORD BOWED RELATIVE TO SAID FIRST CHORD WITH SAID FIRST AND SECOND CHORDS SECURED TO EACH OTHER BY CONNECTOR MEANS AND COMBINED SPACER-CONNECTOR MEANS HAVING A SPACER PORTION AND CONNECTOR PORTIONS COMPRISING A BASE, A PLURALITY OF PRESS MEANS PLACED IN A PREDETERMINED ORIENTATION ON SAID BASE INCLUDING INTERMEDIATE PRESS MEANS AND END PRESS MEANS ON OPPOSITE SIDES OF SAID INTERMEDIATE PRESS MEANS, LOCATOR MEANS FOR POSITIONING SAID FIRST CHORD ON SAID BASE RELATIVE TO SAID PLURALITY OF PRESS MEANS, COMBINED SPACERLOCATOR MEANS LOCATED PROXIMATE SAID INTERMEDIATE PRESS MEANS FOR SPACING SAID SECOND CHORD RELATIVE TO SAID FIRST CHORD AND FOR LOCATING SAID COMBINED SPACER-CONNECTOR MEANS RELATIVE TO SAID FIRST AND SECOND CHORDS, CLAMPING MEANS FOR DEFLECTING SAID SECOND CHORD RELATIVE TO SAID FIRST CHORD AS LIMITED BY SAID COMBINED SPACER-LOCATOR MEANS AND FOR CLAMPING SAID SECOND CHORD RELATIVE TO SAID FIRST CHORD WITH SAID COMBINED SPACER-LOCATOR MEANS THEREBETWEEN, AND CONTROL MEANS FOR CAUSING SAID INTERMEDIATE PRESS MEANS TO PRESS THE CONNECTOR PORTIONS OF SAID COMBINED SPACER-CONNECTOR MEANS INTO SAID FIRST AND SECOND CHORDS AFTER SAID SECOND CHORD HAS BEEN DEFLECTED AND FOR CAUSING SAID END PRESS MEANS TO PRESS SAID CONNECTOR MEANS INTO THE END PORTIONS OF SAID FIRST AND SECOND CHORDS TO THEREBY EFFECTING THE SECURING OF SAID FIRST AND SECOND CHORDS TO EACH OTHER. 